JP2019002140A - Steel form for constructing base mortar and construction method of base mortar using the same - Google Patents

Abstract

To provide a steel form for constructing a base mortar which can make it easier to construct a base mortar provided between a base plate and a base concrete, and can improve durability of the base mortar against repeated stress.SOLUTION: A steel form 1 for constructing a base mortar is used for constructing a base mortar by filling mortar between a base plate of a steel structure and a base concrete that are bound by an anchor bolt. The steel form 1 is constituted of: a flat plate-shaped top plate 2; and a sheathing board 3 hanging down from an outer periphery of the top plate 2 and preventing outflow of mortar. A mortar injection port 5 for injecting the mortar and an anchor bolt insertion hole 6 into which the anchor bolt is inserted are formed in the top plate 2. The steel form 1 has a role of constructing the base mortar and a role of positioning the anchor bolt.SELECTED DRAWING: Figure 1

Description

  The present invention relates to a steel mold for constructing a base mortar by filling a mortar between a base plate and a foundation concrete of a steel structure to be fastened by an anchor bolt, and a base mortar construction method using the same. .

  In anchoring steel structures to anchorage concrete using anchor bolts, anchor bolts are installed and reinforcing bars are placed before the foundation concrete is placed. One steel structure is installed by inserting anchor bolts into anchor bolt insertion holes formed in the base plate. For this reason, the position accuracy of the anchor bolt is highly required and generally needs to be within ± 2.5 mm from the anchor bolt core.

  Due to the high requirement of anchor bolt position accuracy, it is generally called a template at the construction stage, and it is a frame made of steel plates or shaped steel with holes in predetermined positions. The position of the bolt is prevented from shifting.

  There is also a construction method in which the adhesion performance of the bottom surface of the base plate is improved by devising the shape of the base plate, the accuracy required in general is relaxed, and the holes formed in the base plate can be made larger.

  The column base of the steel structure that is installed using anchor bolts is filled with mortar such as non-shrinkable mortar after the installation of the steel structure to fill the gap between the top of the foundation concrete and the base plate. Integration with is aimed at.

  In general, base mortar is constructed for (1) foundation concrete placement, (2) template removal, (3) level mortar (so-called manju) construction, (4) installation of steel structures, (5) mortar (6) Mortar injection in this order. That is, the template is discarded after removal. In addition, it is necessary to install and remove the mold for filling the mortar.

  On the other hand, the number of processes involved in the construction of exposed column bases of steel structures using anchor bolts is large, and site management is complicated. In addition, the template, which is a steel part, has a single use for anchor bolt positioning, and requires a separate formwork for filling the mortar, and wastes material such as removing it after mortar construction. Many.

  Patent Document 1 discloses a method for saving labor of column base work by using a reusable formwork connected by a hinge. And the non-shrink mortar is used as a mortar filled between a base plate and foundation concrete.

  However, this non-shrink mortar is a material with poor toughness, and cracking or peeling off occurs in the base mortar when subjected to excessive force such as seismic force. Therefore, when it receives repeated seismic forces, the axial force support capacity decreases.

  If a base mortar composed of non-shrink mortar, which is a filler, cracks or peels off due to an earthquake or the like, it is necessary to repair after the disaster. The repair work is performed by a method in which a cracked base mortar is picked up, a new formwork is constructed, and the mortar is filled again. Repair of the foundation part requires dismantling of the floor and outer walls, and is burdensome in terms of construction period and cost.

  Non-Patent Document 1 proposes a method of covering the four corners of the base mortar with steel plates as a method for preventing the base mortar from peeling off. However, this method is rarely used from the viewpoint of labor and cost.

JP-A-10-115091

“Steel structural joint design guidelines” Architectural Institute of Japan, p. 262-263, March 2012

  The present invention has been made in order to solve the above-described problems of the prior art, and makes the workability of the base mortar provided between the base plate and the foundation concrete easier and moreover against the repeated stress of the base mortar. It is an object of the present invention to provide a steel mold for base mortar construction that can improve durability and a base mortar construction method using the same.

  According to the present invention, in order to solve the above problems, first, a steel mortar for building a base mortar by filling a mortar between a base plate of a steel structure to be fastened by an anchor bolt and a foundation concrete. The steel formwork is composed of a flat top plate and a sag plate that hangs down from the outer periphery of the top plate and prevents mortar from flowing out, and mortar is injected into the top plate. For base mortar construction, characterized in that a mortar inlet for inserting an anchor bolt and an anchor bolt insertion hole for inserting an anchor bolt are formed, and the base mortar construction serves as a template for positioning the anchor bolt A steel formwork is provided.

  Second, in the first invention, there is provided a steel mold for constructing a base mortar, wherein an opening is provided in a central portion of the top plate so that the base mortar and the base plate can be brought into contact with each other. Provided.

  Thirdly, in the first or second invention, there is provided a steel mold for building a base mortar, wherein an air vent hole is provided in the top plate.

  Fourth, in any one of the first to third aspects of the invention, the steel mold is formed by the top plate having a square shape, and the slats being welded to four sides of the top plate. A steel formwork for building a base mortar is provided.

  Fifth, in any one of the first to third aspects of the invention, the steel mold frame is a single piece in which the top plate has a square shape, and the top plate and the portion that becomes the ceiling plate are integrated. A steel mold for building a base mortar is provided, which is formed by bending a plate and welding and joining four corners.

  Sixth, in any one of the first to third inventions, the steel mold frame is formed by welding and joining the top plate on a frame-shaped frame formed of an equilateral mountain-shaped steel or an unequal mountain-shaped steel. A steel mold for constructing a base mortar is provided.

  Seventh, in any one of the first to third inventions, the steel mold is quadrangular, polygonal, or circular in plan view, depending on the shape of the steel structure. A steel formwork for base mortar construction is provided.

  Eighth, the steel mold for constructing the base mortar according to any one of the first to seventh inventions is attached to the top of the anchor bolt, the foundation concrete is placed, the foundation concrete placed, and the base A base mortar is constructed by injecting mortar from a mortar inlet of the top plate of the steel mold for base mortar construction with a base plate of the steel structure installed on a steel mold for mortar construction. A base mortar construction method is provided.

  According to the present invention, by using a steel mold having a template function, the anchor bolt can be accurately positioned by attaching the steel mold to the top of the anchor bolt, and the mortar construction mold Since the frame will be installed, it will be involved in the column base work. (1) Arrangement of mortar construction formwork separate from anchor bolt positioning, (2) Omission of mold removal and disposal of mortar construction formwork it can. Accordingly, labor costs, material costs, and disposal costs related to the mortar construction form are reduced, leading to cost reduction. Moreover, since the template and the steel formwork remain as they are, it leads to reduction of waste.

  In addition, since the steel formwork constrains the base mortar inside, the toughness of the part is increased, and a joint that does not impair the load transmission performance can be realized even when subjected to seismic force or wind load that repeatedly acts.

  Furthermore, since the mortar is covered with the steel formwork during mortar curing, it is possible to suppress the occurrence of cracks due to drying shrinkage without touching the outside air.

FIG. 3 is a perspective view showing the structure of a steel mold according to an embodiment of the present invention, which has a square top plate with an opening at the center, and has a mortar inlet and an air vent hole formed in the top plate. . It is a figure showing the cross-sectional shape of the steel formwork of one Embodiment of this invention. It is typical sectional drawing showing the state which attached the steel formwork which concerns on one Embodiment of this invention to the anchor bolt set to the anchor frame. It is typical sectional drawing showing the state which attached the steel formwork which concerns on another embodiment of this invention to the anchor bolt set to the anchor frame. It is a figure which shows typically the condition where the base mortar cracked when the joint part of the column base constructed | assembled by the prior art received the horizontal force by an earthquake etc. FIG. It is explanatory drawing of the method of manufacturing the steel formwork of this invention by bending the sheet | seat of the unfolded figure shape with which the square-shaped top plate and the board were integrated. It is a figure showing the cross-sectional shape of the steel formwork manufactured using the angle material (section steel). It is a perspective view which shows the steel formwork whose top plate shape is a polygon in planar view.

  Hereinafter, the present invention will be described in detail based on embodiments.

  FIG. 1 is a perspective view showing the structure of a steel mold for base mortar construction (hereinafter also simply referred to as a steel mold) according to an embodiment of the present invention, and FIG. 2 is a diagram showing a cross-sectional shape of the steel mold. It is.

  This steel mold 1 is composed of a square flat plate 2 and a slat plate 3 that hangs down from the outer periphery (four sides) of the top plate 2 and prevents mortar from flowing out. An opening 4 is provided at the center of the top plate 2. A mortar injection port 5 for injecting a rectangular mortar in a plan view is formed in front of the top plate 2 in FIG. 1, and anchor bolt insertion holes 6 for inserting anchor bolts are formed at four corners. An air vent hole 7 as shown is formed. The air vent hole 7 is provided to inject the mortar without a gap.

  The steel formwork 1 of the present embodiment is used as a template for positioning the base plate with a base mortar, preventing misalignment of the upper part of the anchor bolt, and performing accurate positioning. It serves as the foundation of a steel structure welded and welded together.

  Here, an example of the steel mold dimensions will be described. Generally, the thickness of the base mortar of the exposed column base is about 30 to 60 mm. The top plate of the steel mold has a function to disperse the supporting pressure when receiving bending and axial force acting on the steel structure installed on the upper part and transmitting it to the base mortar. The thickness of the top plate constituting the steel mold is preferably about 1/7 to 1/5 of the thickness of the base mortar from the balance of strength between the base mortar and the steel constituting the steel mold. Then, the top plate thickness is about 4.5 to 12 mm.

  Further, it is desirable that the thickness of the weir plate constituting the steel mold is equal to the thickness of the top plate or one size smaller. As a specific size range, the thickness of the plate is about 3.2 to 12 mm.

  In addition, in this specification, mortar means the cement compounding filler containing non-shrink mortar.

  The opening 4 of the top plate 2 has such a size that a level mortar (so-called “manju”) for adjusting the level of the steel structure to be fixed can be applied. The opening 4 allows the level mortar and the base plate of the steel structure to come into contact with each other.

  The steel mold 1 of the present embodiment has a structure in which a steel plate to be a dam plate 3 is welded around a top plate 2 having an opening 4 as schematically shown in a sectional view in FIG. ing. The height of the weir plate 3 is equal to or higher than the filling height of the mortar. It is conceivable to use a shape steel such as flat steel or equilateral angle steel as the material of the dam plate 3, but it will prevent mortar from flowing out and be sufficiently restrained when an excessive load is applied due to an earthquake or the like after mortar hardening. It is good if it has enough strength.

  FIG. 3 is a cross-sectional view schematically showing a state in which the steel mold 1 of the present embodiment is attached to the anchor bolt 12 set on the anchor frame 11. FIG. 3 also shows a state in which the steel mold of this embodiment is attached to the exposed column base of the steel structure.

  Installation of the anchor bolts 12 at the column base is performed when abandoned concrete (also referred to as abandoned concrete) 13 on the bottom surface of the foundation is completed. A steel base member 14 is attached to the upper surface of the discarded concrete, and an anchor frame 11 made of shape steel is raised on the base member 14. The anchor frame 11 temporarily fixes the anchor bolt 12. After completion of anchor frame installation, the fixing plate 15 and the anchor bolt 12 are attached to the anchor frame 11. Thereafter, in order to prevent displacement of the upper part of the anchor bolt, a steel mold 1 having a template function is covered and temporarily fixed with a nut 16.

  Next, foundation concrete 17 is laid. A vibrator is used for placing the foundation concrete 17. 18 is the top of the foundation concrete.

  Next, level mortar (not shown) is applied, and then the steel structure is installed. In FIG. 3, 19 is a steel column of a steel structure, and 20 is a base plate.

  Next, the base mortar 21 is constructed between the base plate 20 of the steel structure and the foundation concrete 17 by filling mortar (non-shrink mortar) from the mortar inlet 5 of the steel mold 1 of the present embodiment. .

  The steel formwork of the present embodiment is left as it is without being removed after the construction of the base mortar. By using a steel mold that does not need to be removed, the base mortar is in a state where the four sides are constrained by a steel mold. As a result, even if the stress applied to the base mortar due to the bending moment, which is generated mainly when a horizontal force is applied, disperses and cracks occur in the base mortar, the formwork restrains the base mortar and peels off. Can be prevented. Therefore, it is expected that the toughness of the filler portion is increased even during an earthquake or storm subjected to a large number of repeated loads, and it is difficult to cause brittle fracture.

  Generally, when a steel structure is damaged by an earthquake or the like, many cracks and peeling off occur in the mortar used as a filler, and the repair takes time and cost. On the other hand, when the steel formwork of this embodiment is used, the toughness of the filler portion is increased, so that repair after being damaged by an earthquake or the like is unnecessary or greatly reduced, so that the structure after the disaster is Continued use is quick and easy.

  Here, as an experimental example for confirming the effect of the steel formwork, a column base loading test with a base plate yielding type element is taken up. The base plate yield type has a larger bearing stress acting on the top plate than a general anchor bolt yield type column base. As a result of the experiment, peeling of the base mortar often observed in the damaged exposed column base did not occur, and the base mortar portion maintained the original shape. As a result, it has been demonstrated that it can continue to be used for aftershocks and repeated large earthquakes, and it can be repaired after the disaster.

  Moreover, the non-shrink mortar generally used as a filler is likely to be cracked by drying of the surface, and needs to be kept wet during curing. On the other hand, by using the steel formwork of this embodiment, the base mortar is not exposed and does not come into contact with the outside air, so that cracks due to dry operation shrinkage can be prevented and construction quality can be improved.

  Moreover, in order to give the function as a template to the top plate of the steel formwork of this embodiment, an anchor bolt insertion hole through which the anchor bolt penetrates is provided. For this reason, when the steel formwork of this embodiment is used, it becomes possible to perform the construction of the base mortar and the positioning of the anchor bolt with high accuracy with one member.

  Moreover, in order to fill the concrete with a vibrator when placing the foundation concrete, it is desirable that an opening to the extent that the work with the vibrator can be performed is provided in the center of the top plate. Moreover, by making the opening of the top plate close to the same size as the base plate of the column base, the base plate and the base mortar come into contact with each other, and the shear strength due to friction can be ensured.

  In the above-described embodiment, the steel mold form in which the top plate is provided with the opening is described. However, according to the present invention, as shown in FIG. 4, the opening 4 is not provided in the central portion of the top plate of the steel mold frame. The steel structure can also be placed on the top plate. In this case, only the mortar inlet 5, the bolt hole 6, and the air vent hole 7 are opened in the top plate 2. At that time, it is desirable to apply a friction surface treatment for applying a friction force between the contact surfaces of the steel structure and the steel mold.

  FIG. 5 shows a situation where the exposed column base of a steel building constructed by a conventional technique receives a horizontal force such as seismic force. In FIG. 5, 21 is foundation concrete, 22 is base mortar, 23 is a base plate, 24 is a nut. When the exposed column base receives a horizontal force, a bending moment is generated at the lower end of the column and one side is lifted. In the conventional technology, since the bearing pressure due to the column floating directly acts on the base mortar, cracking and peeling off occur after the disaster. According to the steel mold 1 of this embodiment, such a problem can be solved.

  As mentioned above, although this invention was demonstrated based on one Embodiment, this invention is not limited to this embodiment, A various deformation | transformation and change are possible.

  For example, in the above-described embodiment, the steel mold is manufactured by welding and joining a steel plate that is a sill plate around the top plate having an opening, but a different structure is obtained by using another manufacturing method. be able to.

  FIG. 6 shows another example of the steel mold manufacturing method. In this example, an opening 4, a mortar inlet 5, an anchor bolt insertion hole 6, and an air vent hole 7 necessary for the top plate 2 are formed in a steel plate larger than the top plate 2, and the four corners are cut into squares. Thereafter, the steel mold 1 is manufactured by bending the steel plate at a right angle along the side of the square notch at the corner and welding the four corners. In this way, since a formwork can be manufactured from one steel plate, further improvement in productivity is expected.

  FIG. 7 shows still another example of the steel mold manufacturing method. In this example, the weir plate 3 is made of a shape steel (angle material) such as an equilateral angle steel or an unequal angle iron, and a steel plate which becomes the top plate 2 is placed on a frame-like frame made of the shape steel. Mount, weld or join with bolts to integrate. If it does in this way, since the intensity | strength of a bottom plate part will increase, the performance which restrains a base mortar can be improved more.

  Moreover, in the said embodiment, although the top plate was made into the square square of planar view, you may make a top plate into polygonal shape like FIG. When the cross-sectional shape of the column of the steel structure to be fixed is not a square, but a polygon, the shape of the base plate may be a polygon. In order to cope with such a situation, the steel mold can also be a polygon that matches the shape of the base plate. The steel mold can also be circular.

DESCRIPTION OF SYMBOLS 1 Steel formwork 2 Top plate 3 Baffle plate 4 Opening 5 Mortar injection port 6 Anchor bolt injection hole 7 Air vent hole 11 Anchor frame 12 Anchor bolt 13 Discarded concrete 14 Base member 15 Fixing plate 16 Nut 17 Foundation concrete 18 Foundation concrete top edge 19 Steel column 20 Base plate 21 Base mortar

Claims (8)

A steel formwork for constructing a base mortar by filling a mortar between a base plate of a steel structure to be fastened by an anchor bolt and foundation concrete,
The steel mold is constituted by a flat top plate and a sag plate that hangs down from the outer periphery of the top plate and prevents mortar from flowing out,
The top plate is formed with a mortar inlet for injecting mortar and an anchor bolt insertion hole for inserting an anchor bolt, and has a role of a template for positioning the anchor bolt along with the construction of the base mortar. A steel formwork for building base mortar, characterized by   The steel mold for constructing a base mortar according to claim 1, wherein an opening is provided in a central portion of the top plate so that the base mortar and the base plate can come into contact with each other.   The steel plate for base mortar construction according to claim 1, wherein an air vent hole is provided in the top plate.   4. The steel formwork according to claim 1, wherein the top plate has a square shape, and the weir plates are welded to four sides of the top plate, respectively. 5. Steel mold for base mortar construction as described in 1.   The steel mold is formed by bending the single plate in which the top plate is square-shaped, the top plate and the part to be the sill plate are integrated, and welding the four corners. The steel mold for base mortar construction according to any one of claims 1 to 3.   The steel mold is formed by welding and joining the top plate on a frame-like frame made of equilateral chevron or unequal chevron. Steel mold for base mortar construction given in any 1 paragraph.   The base mortar construction according to any one of claims 1 to 3, wherein the steel mold is quadrangular, polygonal or circular in plan view according to the shape of the steel structure. Steel formwork.   The base mortar construction steel form according to any one of claims 1 to 7 is attached to the top of the anchor bolt, the foundation concrete is cast, the cast foundation concrete, and the base mortar construction steel form The base mortar is constructed by injecting mortar from the mortar inlet of the top plate of the steel mold for constructing the base mortar between the base plate of the steel structure mounted on the base Method.